Blade-carrier tools, in particular for cutting floor coverings, comprise a handle for grasping which is generally constituted by two assembled-together half-shells, with a cutter blade being disposed therebetween so that a portion thereof projects from one of their common ends. A clamping mechanism including a screw serves to hold the two half-shells together and consequently to hold the cutter blade in position with the blade thus being pressed on opposite sides by the half-shells.
Although tools of this type are in very widespread use, they nevertheless suffer from the drawback of requiring a screwdriver to be available for opening the handle for the purpose of changing the blade, and subsequently for closing it again in order to hold the new blade in position. Consequently, that requires fiddly disassembly and assembly operations on the screw, and it requires the two half-shells to be fitted together properly before they can be screwed together.
Another type of blade-carrier tool is also known for cutting floor coverings which avoids the need for a screwdriver and in which the two half-shells are moved apart for the purpose of changing a blade and are moved back towards each other for the purpose of holding a new blade in position by means of a screw clamping mechanism provided with a knurled disk disposed in the mean plane common to the two assembled-together half-shells and projecting therefrom. The handle of the tool can thus be opened and closed by acting directly on the knurled disk that is secured to the screw which holds the two half-shells together.
Although that considerably improves the use of such tools, the proper clamping torque is not always applied to the disk to ensure that the handle is closed securely. Thus, if too little clamping torque is applied, there is a danger of the blade slipping suddenly between the two half-shells, and in the application described that can give rise to dangerous and inaccurate cutting of the covering, while if the clamping torque is too great, then the handle can be opened again only by acting on the disk by means of a suitable tool.
An object of the present invention is to remedy the above drawbacks by providing a blade-carrier tool whose clamping mechanism design makes it possible to do without a screwdriver or other similar tool when changing the blade, and makes it possible to open and close said blade-carrier tool automatically.